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Weil-McLain WTGO-4 Tankless Water Heater and Storage Tank Configuration - Advice Needed

Hi. I recently bought a house that was built in 2007 and has a Weil-McLain WTGO-4 oil fired boiler. The tankless domestic hot water coil is connected to a State electric water heater/storage tank. It appears that the system is configured to use the WTGO-4 for domestic hot water in the heating season and electricity in the summer. Attached is a picture of the system. The house has plenty of hot water so far but I have only used it in the winter when the boiler is operating. What is the best configuration of winter/summer operation? One concern I have is the water temperature. Not sure how the maximum water temperature is set in this system. Appreciate any advice/guidance you can provide as I want to make sure the system is installed/configured properly. Thanks and best regards.


  • icesailor
    icesailor Member Posts: 7,265
    That installer did a really nice job.

    I'm sure that he has his reasons for installing that water heater that way. A lot of people think that's the way to go. I don't do it like that. I have done it like that long ago in the past. I found another way works better and cost less to operate. If someone tells you that's the best way, they must know what they are talking about. It wasn't better for me and all the ones I did my way.

    Mine's simplicity. That one isn't. It works though.
  • damejoe
    damejoe Member Posts: 2
    Icesailor: Thanks. I also reviewed your previous posts and pictures. They are great - I now understand the system and how it works. I noticed that my WTGO-4 boiler and storage tank system do not have the Taco circulator pump installed. I like the way you set up your system and will add a circulator pump in the future. Thanks again and best regards.
  • icesailor
    icesailor Member Posts: 7,265
    Understand that, you don't leave the water heater connected to the 220 volt, 30 amp circuit. And you don't need that thermostatic mixer any more. All water (cold and hot) goes through the tank. . It only goes through the coil through the circulator.

    You could actually leave the 220 wiring connected and use the electric in the summer. But there's things you have to do.

    Its my personal experience that the additional electric cost doesn't justify the switch over. That the savings on oil cost doesn't justify the additional electric cost. For you, it might be more of a wash because I always factored in the additional cost of the electrical wiring for the water heater. When you do it with a pump, you only use the bottom thermostat as a switch. You don't need the thermostatic mixer now there because the thermostat on the water heater does the temperature controlling.

    You get the additional benefit of boiler protection (water 140 degrees) and the high limit can be set to 160 degrees. Lower system temperature, but if it gets really cold and the system isn't keeping up, you just raise the high limit to 170 or 180 degrees until it warms up. You get 18 GPH recovery with the electric water heater, but that boiler/tankless is rated at 3 to 4 GPM recovery which means 180 to 240 GPH of recovered hot water.

    If you have high loads, you'll be happy.

    If you've ever tried to give your dog a bath with cold water, the dog is not happy. If it is warm water, they look forward to a nice warm bath. Like we enjoy a nice hot shower.

    My wife bathes her horse in warm water. Horses aren't stupid. If you try to bath them in cold water, you have to beat them like you own them to get them to the wash stall place. If the water is warm, you just let them go. They go and stand there waiting. If the water went cold, both my wife and her horse would be upset. The horse isn't as much of a problem. Its my wife.

    If I had it to do over, I'd only have horses. No children. Horses don't sneak out at night and "borrow" your cars, get lit up and crash the borrowed car. They never get gripey and complain, they stay in their rooms/stalls when you put them there, and they don't get knocked up by being sneaky by riding around with boys in cars. The "Boys" have most all had their boy equipment removed.

    And they are always glad to see you when you feed them or bring them treats.